Magnetic recording elements in the form of tape and disks are well known in the art. Disk elements have been widely accepted in the industry for use in both fixed file units, such as the initial IBM 305 RAMAC of the 1950's, and subsequent disk products such as the IBM 5440 Disk Cartridge, more fully described in U.S. Pat. No. 3,635,608; in the IBM 1316 Disk Pack, more fully described in U.S. Pat. Nos. 3,176,281 and 3,206,214; in the IBM 2315 Disk Cartridge, more fully described in U.S. Pat. Nos. 3,526,884 and 3,304,544; and other well known disk products, such as the IBM 3336 Disk Pack, and the IBM 3840 Data Module. Each of the above is characterized in having at least one magnetic recording element including a base, such as an aluminum substrate and a polymeric coating upon a surface of the base, such as an epoxy phenolic resin, the coating further comprising magnetic particles such as iron oxide dispersed in the binder. Further, the cartridges noted above are contained in a separate housing for insertion with the housing onto a record processing machine. When placed upon the machine, separate transducer means is permitted to enter into the housing to interact with the magnetic recording element.
The disk packs by contrast do not have their own housing, but are mounted upon a spindle for rotation therewith. The pack is removably placed upon the record processing machine. Separate accessing means from the machine are also used for disk accessing. In the data module noted above, however, the heads are contained within the housing, the entire module being removable from the record processing machine. Fixed files are well known in the art, and may have fixed or movable heads as desired.
In each of these systems, rotational speeds of up to 3600 revolutions per minute or more may be attained. The accessing means, generally magnetic transducer means, fly in close relationship to the disk upon an air bearing caused by the rotation of the disk and the aerodynamic design of the head. These heads may fly as close as 30 microinches, or even closer, from the surface of the disk. While every effort is made to assure that disk surface topography is as flat and perfect a surface as possible, the possibility exists that the head may be caused to come into contact with the disk due to a local asperity in the surface of the disk, or from dirt entering between the head and disk. This "crashing" can cause a loss of data, and serious damage to the head and the disk. Further, systems have been envisioned in which the head will start by sitting upon the disk, and will not begin to fly until a minimum rotational speed is achieved. Similarly, stopping will allow the head to slowly glide to a halt upon the disk surface.
In the above circumstances, damage to the disk must be minimized to maintain the data stored in the disk coating. Thus, many different lubricant systems have been proposed, including various silicones for example, and lubricating oils incorporated within the recording coating itself, or as additives upon the surface. Some have proven successful to a limited degree.
Thus, an object of this invention is a lubricant of high wear characteristics that may be used with magnetic recording elements in tape or disk form.
A further object is a lubricant that does not adversely affect the adhesion of the magnetic recording medium to the underlying base or substrate, nor will affect the magnetic properties thereof.
A further object is a lubricant having long life and that is inexpensive and readily incorporated into the coating or upon the coating as desired.